From: Boqun Feng <boqun@kernel.org>
To: Peter Zijlstra <peterz@infradead.org>
Cc: "Catalin Marinas" <catalin.marinas@arm.com>,
"Will Deacon" <will@kernel.org>,
"Jonas Bonn" <jonas@southpole.se>,
"Stefan Kristiansson" <stefan.kristiansson@saunalahti.fi>,
"Stafford Horne" <shorne@gmail.com>,
"Heiko Carstens" <hca@linux.ibm.com>,
"Vasily Gorbik" <gor@linux.ibm.com>,
"Alexander Gordeev" <agordeev@linux.ibm.com>,
"Christian Borntraeger" <borntraeger@linux.ibm.com>,
"Sven Schnelle" <svens@linux.ibm.com>,
"Thomas Gleixner" <tglx@kernel.org>,
"Ingo Molnar" <mingo@redhat.com>,
"Borislav Petkov" <bp@alien8.de>,
"Dave Hansen" <dave.hansen@linux.intel.com>,
x86@kernel.org, "H. Peter Anvin" <hpa@zytor.com>,
"Arnd Bergmann" <arnd@arndb.de>,
"Juri Lelli" <juri.lelli@redhat.com>,
"Vincent Guittot" <vincent.guittot@linaro.org>,
"Dietmar Eggemann" <dietmar.eggemann@arm.com>,
"Steven Rostedt" <rostedt@goodmis.org>,
"Ben Segall" <bsegall@google.com>, "Mel Gorman" <mgorman@suse.de>,
"Valentin Schneider" <vschneid@redhat.com>,
"K Prateek Nayak" <kprateek.nayak@amd.com>,
"Boqun Feng" <boqun@kernel.org>,
"Waiman Long" <longman@redhat.com>,
"Andrew Morton" <akpm@linux-foundation.org>,
"Andrii Nakryiko" <andrii@kernel.org>,
"Eduard Zingerman" <eddyz87@gmail.com>,
"Alexei Starovoitov" <ast@kernel.org>,
"Daniel Borkmann" <daniel@iogearbox.net>,
"Martin KaFai Lau" <martin.lau@linux.dev>,
"Kumar Kartikeya Dwivedi" <memxor@gmail.com>,
"Song Liu" <song@kernel.org>,
"Yonghong Song" <yonghong.song@linux.dev>,
"Jiri Olsa" <jolsa@kernel.org>, "Shuah Khan" <shuah@kernel.org>,
"Miguel Ojeda" <ojeda@kernel.org>, "Gary Guo" <gary@garyguo.net>,
"Björn Roy Baron" <bjorn3_gh@protonmail.com>,
"Benno Lossin" <lossin@kernel.org>,
"Andreas Hindborg" <a.hindborg@kernel.org>,
"Alice Ryhl" <aliceryhl@google.com>,
"Trevor Gross" <tmgross@umich.edu>,
"Danilo Krummrich" <dakr@kernel.org>,
"Jinjie Ruan" <ruanjinjie@huawei.com>,
"Lyude Paul" <lyude@redhat.com>, "Thomas Huth" <thuth@redhat.com>,
"Sohil Mehta" <sohil.mehta@intel.com>,
"Xin Li (Intel)" <xin@zytor.com>,
"Pawan Gupta" <pawan.kumar.gupta@linux.intel.com>,
"Nikunj A Dadhania" <nikunj@amd.com>,
"Joel Fernandes" <joelagnelf@nvidia.com>,
"Andy Shevchenko" <andriy.shevchenko@linux.intel.com>,
"Randy Dunlap" <rdunlap@infradead.org>,
"Yury Norov" <ynorov@nvidia.com>,
"Sebastian Andrzej Siewior" <bigeasy@linutronix.de>,
linux-kernel@vger.kernel.org, linux-openrisc@vger.kernel.org,
linux-s390@vger.kernel.org, linux-arch@vger.kernel.org,
bpf@vger.kernel.org, linux-kselftest@vger.kernel.org,
rust-for-linux@vger.kernel.org, "Onur Özkan" <work@onurozkan.dev>,
"Daniel Almeida" <daniel.almeida@collabora.com>
Subject: [PATCH v2 11/12] arm64: sched/preempt: Enable HAS_SEPARATE_PREEMPT_RESCHED_BITS
Date: Tue, 26 May 2026 08:21:47 -0700 [thread overview]
Message-ID: <20260526152148.30514-12-boqun@kernel.org> (raw)
In-Reply-To: <20260526152148.30514-1-boqun@kernel.org>
ARM64 already uses 64bit preempt count and the need reschedule bit is
maintained in a separate 32bit than the preempt count. Therefore preempt
count has enough bits to represent 16 level of NMI nesting, hence enable
it for ARM64. This saves a per-CPU variable and additional instructions
in the NMI path.
Signed-off-by: Boqun Feng <boqun@kernel.org>
---
arch/arm64/Kconfig | 1 +
1 file changed, 1 insertion(+)
diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig
index fe60738e5943..8178cb857115 100644
--- a/arch/arm64/Kconfig
+++ b/arch/arm64/Kconfig
@@ -248,6 +248,7 @@ config ARM64
select PCI_SYSCALL if PCI
select POWER_RESET
select POWER_SUPPLY
+ select HAS_SEPARATE_PREEMPT_RESCHED_BITS
select SPARSE_IRQ
select SWIOTLB
select SYSCTL_EXCEPTION_TRACE
--
2.50.1 (Apple Git-155)
next prev parent reply other threads:[~2026-05-26 15:22 UTC|newest]
Thread overview: 24+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-05-26 15:21 [PATCH v2 00/12] Refcounted interrupt disable and SpinLockIrq for rust (Part 1) Boqun Feng
2026-05-26 15:21 ` [PATCH v2 01/12] preempt: Track NMI nesting to separate per-CPU counter Boqun Feng
2026-05-26 15:21 ` [PATCH v2 02/12] preempt: Introduce HARDIRQ_DISABLE_BITS Boqun Feng
2026-05-26 15:21 ` [PATCH v2 03/12] preempt: Introduce __preempt_count_{sub, add}_return() Boqun Feng
2026-05-26 15:21 ` [PATCH v2 04/12] openrisc: Include <linux/cpumask.h> in smp.h Boqun Feng
2026-05-26 15:21 ` [PATCH v2 05/12] irq & spin_lock: Add counted interrupt disabling/enabling Boqun Feng
2026-05-26 16:19 ` bot+bpf-ci
2026-05-28 10:43 ` Peter Zijlstra
2026-05-28 14:31 ` Boqun Feng
2026-05-26 15:21 ` [PATCH v2 06/12] irq: Add KUnit test for refcounted interrupt enable/disable Boqun Feng
2026-05-26 15:21 ` [PATCH v2 07/12] locking: Switch to _irq_{disable,enable}() variants in cleanup guards Boqun Feng
2026-05-28 10:45 ` Peter Zijlstra
2026-05-28 14:31 ` Boqun Feng
2026-05-26 15:21 ` [PATCH v2 08/12] sched: Remove the unused preempt_offset parameter of __cant_sleep() Boqun Feng
2026-05-26 15:21 ` [PATCH v2 09/12] sched: Avoid signed comparison of preempt_count() in __cant_migrate() Boqun Feng
2026-05-26 15:21 ` [PATCH v2 10/12] preempt: Introduce HAS_SEPARATE_PREEMPT_RESCHED_BITS Boqun Feng
2026-05-26 15:21 ` Boqun Feng [this message]
2026-05-28 10:50 ` [PATCH v2 11/12] arm64: sched/preempt: Enable HAS_SEPARATE_PREEMPT_RESCHED_BITS Peter Zijlstra
2026-05-26 15:21 ` [PATCH v2 12/12] s390/preempt: " Boqun Feng
2026-05-28 10:53 ` Peter Zijlstra
2026-05-28 14:41 ` Boqun Feng
2026-05-28 15:18 ` Heiko Carstens
2026-05-27 16:18 ` [PATCH v2 00/12] Refcounted interrupt disable and SpinLockIrq for rust (Part 1) Peter Zijlstra
2026-05-27 16:33 ` Boqun Feng
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20260526152148.30514-12-boqun@kernel.org \
--to=boqun@kernel.org \
--cc=a.hindborg@kernel.org \
--cc=agordeev@linux.ibm.com \
--cc=akpm@linux-foundation.org \
--cc=aliceryhl@google.com \
--cc=andrii@kernel.org \
--cc=andriy.shevchenko@linux.intel.com \
--cc=arnd@arndb.de \
--cc=ast@kernel.org \
--cc=bigeasy@linutronix.de \
--cc=bjorn3_gh@protonmail.com \
--cc=borntraeger@linux.ibm.com \
--cc=bp@alien8.de \
--cc=bpf@vger.kernel.org \
--cc=bsegall@google.com \
--cc=catalin.marinas@arm.com \
--cc=dakr@kernel.org \
--cc=daniel.almeida@collabora.com \
--cc=daniel@iogearbox.net \
--cc=dave.hansen@linux.intel.com \
--cc=dietmar.eggemann@arm.com \
--cc=eddyz87@gmail.com \
--cc=gary@garyguo.net \
--cc=gor@linux.ibm.com \
--cc=hca@linux.ibm.com \
--cc=hpa@zytor.com \
--cc=joelagnelf@nvidia.com \
--cc=jolsa@kernel.org \
--cc=jonas@southpole.se \
--cc=juri.lelli@redhat.com \
--cc=kprateek.nayak@amd.com \
--cc=linux-arch@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-kselftest@vger.kernel.org \
--cc=linux-openrisc@vger.kernel.org \
--cc=linux-s390@vger.kernel.org \
--cc=longman@redhat.com \
--cc=lossin@kernel.org \
--cc=lyude@redhat.com \
--cc=martin.lau@linux.dev \
--cc=memxor@gmail.com \
--cc=mgorman@suse.de \
--cc=mingo@redhat.com \
--cc=nikunj@amd.com \
--cc=ojeda@kernel.org \
--cc=pawan.kumar.gupta@linux.intel.com \
--cc=peterz@infradead.org \
--cc=rdunlap@infradead.org \
--cc=rostedt@goodmis.org \
--cc=ruanjinjie@huawei.com \
--cc=rust-for-linux@vger.kernel.org \
--cc=shorne@gmail.com \
--cc=shuah@kernel.org \
--cc=sohil.mehta@intel.com \
--cc=song@kernel.org \
--cc=stefan.kristiansson@saunalahti.fi \
--cc=svens@linux.ibm.com \
--cc=tglx@kernel.org \
--cc=thuth@redhat.com \
--cc=tmgross@umich.edu \
--cc=vincent.guittot@linaro.org \
--cc=vschneid@redhat.com \
--cc=will@kernel.org \
--cc=work@onurozkan.dev \
--cc=x86@kernel.org \
--cc=xin@zytor.com \
--cc=ynorov@nvidia.com \
--cc=yonghong.song@linux.dev \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox